Ground Zero was still a very tenuous site as construction crews tried to pick up the pieces with the horrible tragedy in the back of mind. One of those crews was Ziegenfuss Drilling Inc., a New Jersey-based drilling company that specializes in commercial water wells, foundations work, mine and tunnel projects, mostly in the East Coast of the United States. 

Ziegenfuss had one main job: secure the site's main foundation as fears that the nearby Hudson River would overtake the subway floor and risk further flooding. Five years ago, The Driller sat down with Mark Ziegenfuss, the company’s founder to recall the day his drilling team answered the call. 

Here’s an excerpt of his sit down with us, or you can read the full Q&A, right here. 

The Driller: Before we get into the specifics of the work, how did you get that project? Was it a bid, networking or a call out of the blue based on your company’s reputation/expertise?

Mark Ziegenfuss:  It wasn’t a bid. … We were the first ones asked to go there. The reason we were asked to go there was the drilling equipment that we have was kind of unique. It’s able to drill through a lot of obstructions. That’s where we got a lot of our work. They had a lot of obstructions there by the outside walls and Trade Center. What they wanted us to do was to drill down below the basement. They called it the “bathtub” of the World Trade Center…If you look at the pictures that we have, when we moved in there, there’s smoke coming up from the rubble from all the steel. When they built the building, they put the tiebacks in to hold the wall. You have the wall and, at about a 30-degree angle, you have a tieback that goes into the rocks to hold that wall up. What I didn’t know was when they put the steel inside the basement they cut the tiebacks to let the wall come in against the inside structural steel. ... When they built it, they released those tiebacks. 

So now ... you have smoke coming up through the steel. We were told it was still, I believe, 2,100 degrees down at the bottom of the bathtub or basement, whichever you want to call it. What they believed was going to happen was, I believe the subway came in under the World Trade Center and [they thought] all that heat was going to collapse the concrete walls, and all the water pressure from the Hudson was going to come in. That would have been to sea level up to the surface, but the problem was they thought the subway system was going to flood all the way up to 52nd Street, which is above the Lincoln Tunnel. ...

Moretrench America had the dewatering project, and they asked us to go in and do the drilling because they knew we could get through the material there quicker than probably anyone else could. That’s how we got it.

You can read the full conversation with Mark Ziegenfuss who recalls his role in the aftermath of 9/11 right here.